The sensitivity of an accelerometer can be degraded by creep of bonded joints. It can also be degraded by a difference in the coefficient of thermal expansion (CTE) between the bonding solder or glue and the bonded pieces.
The resonators and damping plates are typically attached employing either solder or glue. Glue, and to a lesser degree solder, may creep (the tendency of a solid material to slowly move or deform under the influence of stress), thus degrading the sensitivity of the accelerometer.
In addition, the sensitivity of an accelerometer can be degraded by machining imperfections in the proof mass hinge. Machining the hinge can introduce microcracking in the hinge, resulting in loss of accelerometer sensitivity and/or hinge failure.
One way to manufacture a hinge is to glue or solder a thin blank between four proof mass sections. Once again, creep of the solder or glue, as well as the CTE mismatched between the solder or the glue and the proof mass material, will degrade sensitivity.